public class str {
	public static void main(String[] args) {
		StringBuffer builder = new StringBuffer();
		builder.append("hell");
		builder.append("o");
		System.out.println(builder);
		builder.setCharAt(1, 's');
		System.out.println(builder);
		builder.setCharAt(1, 'e');
		builder.insert(5, '!');
		System.out.println(builder);
		builder.delete(1, 4);
		System.out.println(builder);
	}		
}
